Method and device for manufacturing hollow, internally cooled valves
AssigneeFederal-Mogul Valvetrain GmbH
InventorsThorsten Matthias, Dirk Schober
Life of this patent
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Abstract
A method for shaping a hollow valve preform of a pull rod (20) includes a structuring bulb (22) which is inserted into the cavity (56) of a shaft portion (44) of a valve preform. The structuring bulb (22) has an outer diameter, and has an outer structuring, whereafter the hollow shaft portion (44) is shaped, wherein at least a portion of an inner diameter of the cavity (56) is reduced below an outer diameter of the structuring bulb (22). The structuring bulb (22) is then pulled out through the shaped shaft portion (44), wherein the outer structuring is at least partially pressed into the surface of the cavity (56).
Claims12
A method for shaping a hollow valve preform comprising:
- providing a valve preform, which comprises a head portion and a hollow shaft portion comprising a cavity, wherein the shaft portion has an initial outer diameter and an initial inner diameter,
- providing a pull rod having an enlarged structuring bulb at an insertion end of the pull rod that is smaller in outer diameter than the initial inner diameter of the hollow shaft portion of the valve preform,
- inserting the pull rod and structuring bulb into the cavity, wherein the structuring bulb has an outer structuring,
- shaping the hollow shaft portion, wherein at least a portion of an inner diameter of the shaft portion is reduced to be less than the outer diameter of the structuring bulb, and
- therefore pulling out the structuring bulb through the shaped shaft portion, wherein the outer structuring of the structuring bulb is at least partially pressed into the reduced inner diameter surface of the shaft portion to shape the inner diameter surface.
Dependencies are inferred from the claim text.